Boom-drag-line excavator



W. H. CRAWFORD.

BOOM DRAG LINE EXCAVATOR. APPLICATION FILED MAR. 22. 1920.

Patented D60. 27, 1921.

SHEET 1.

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BOOM DRAG LINE EXCAVATOR.

APPLICATION mm mm. 22. 1920.

1,401,319, Patented Dec. 27, 1921.

2 $HEETS-SHEET 2- :H :E.?ol 8 4 l9 l I7 .1171 2 0 INVENTOI? WH Gran f0 rd UNITED STATES PATENT OFFICE.

WILLIAM H. CRAWFORD, 01 LOS ANGELES, CALIFORNIA, ASSIGNOR T0 CHARLOTTE E.

CRAWFORD, OF LOS ANGELES, CALIFORNIA. I

BOOM-DRAG-LINE EXCAVATOR.

Specification of Letters Patent.

Patented Dec. 27, 1921.

To all whom it may concern:

Be it known that I, WILLIAM H. CRAW- FORD, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented new and useful Improvements in Boom-Drag-Line Excavators, of which the following is a specification.

This invention relates to boom drag line excavators and has for its object the provision of novel means whereby the bucket of the excavator will be automatically dumped when it has been hoisted to a predetermined height.

It is a further object of the invention to provide means for adjusting the automatic dumping mechanism to cause the bucket to dump at any desired height.

Other objects of the invention willbe readily understood from the following de scription of the accompanying drawings in which; I

Figure 1 is a side elevation diagrammatically illustrating an excavator: constructed in accordance with my invention with the bucket of the excavator in lowered excavating position.

1g. 2 1s a similar view with the bucket in raised dumping position.

F ig. 3 is an enlarged side elevation of the excavator bucket and its supporting pulley. Fig. 4 is a. top planview of the same.

Fig. 5is an enlarged horizontal section through the supporting pulley taken on the line 5--5 of Fig. 3.

.In the accompan 'ng drawings I have diagrammatically. i1 ustrated an excavator comprisin a usual truck 1 having the cab 2 in whic is carried the usual engine and hoisting drums. The cab 2 is mounted for rotation upon the truck 1 in the usual manner. A standard boom 3 projects outwardly and upwardly from the cab and may be raised and lowered in the usual manner through a cable 4 connected to its outer end and moving over a pulley 5 on the cab to the winding drums within the cab.

The excavator bucket 6 may be of usual construction including the shovel lip 7 atthe open end of the bucket. The drag line 8, moving over a pulley 9 to the winding drums within the cab 2, is attached to the front open end of the bucket for dragging the hue et forward to fill the same in usual manner. The drag line 8 may be attached to the excavating bucket at adjusted heights as shown at 10, in any preferred or well known manner.

The excavator bucket when hoisted is supported from a multiple pulley block. This pulley block comprises a central pulley 12 and pulleys 13 and 14 at the opposite sides thereof, the said pulleys being concentrically arranged upon a shaft 15 with the pulle 13 loose thereon, and the pulleys 12 and 14 keyed thereto as shown at 16.

The pulleys 13 and 14 are employed in connection with thehoisting cable 17, this cable being shown as connected at one end to the end of boom 3 as shown at 18 and running therefrom down over the rear of pulley 14 and around the same in the direction indicated by thearrow in Fi 3, and then up and over a pulley l9 journa led upon the boom 3 and then back down and around the rear of pulley 13 in the direction indicated by the arrow in Fig. 3, and thence up and over a pulley 20 j ournaled upon the end of boom 3 and to the winding drums within the cab of the excavator. By this arrangement the pulleys 13 and 14 form a balanced construction preventing binding of the sup porting pulley block and permitting free rotation thereof. By the construction as thus described itwill be seen that when the winding drum for the cable 17 is rotated in a direction to Wind the cable upon said drum the supporting pulley block for the excavator bucket will be raised and rotated at the same time in the direction indicated by the arrow in Fig. 3; and when the cable is unwound the supporting pulley block will be lowered and rotated in the opposite direction.

The excavator bucket is connected to the supporting pulley block so as to be raised and lowered therewith, said. connection also comprising means for moving the supporting pulley block relative to the excavator bucket from the position shown in Fig. 1, in which the supporting pulley block is above the center of gravity of the bucket thereby maintaining the bucket in normal horizontal position, to the position shown in Fig. 2 wherein the supporting pulley block is above the rear end of the excavator bucket at onev side of its center of gravity, thereby causing the forward weighted end 21 of the bucket to tilt downwardly and dump the latter in usual manner.

As an instance of this arrangement the pulley 12 is, preferably, a double grooved 23 of pulley 12. The cables 24 and 25 are so arranged that when the excavator bucket is in lowered position, as shown in Fig. 1, with the supporting pulley block above the forward weighted end 21 of the bucket, in which position the supporting pulley block is above the center of gravity of the bucket, the

' cable 25 will be wound upon the pulley 12 and cable 24 will'be unwound therefrom.

As the excavator bucket is hoist-ed the su porting pulley block will be rotated in t 1e direction indicated by the arrow in 8, aspreviously described, and cable 24 will be wound upon thepulley 12 and cable 25 will be unwound therefrom, the supporting pulley block thus being moved rearwardly relative to the excavator bucket to the position indicated in Fig. 2 in which position the weighted forward end of the bucket will cause the latter to dump. When the bucket is again lowered to excavating position, as shown in Fig. 1, the supporting pulley block being rotated in; the opposite direction will cause cable 25 to be wound upon pulley 12 and cable 24 to be unwound therefrom, thereby again moving thesupporting pulley block to its position above the center of gravityof the excavator bucket as shown in Fig. 1, thereby supporting the bucket in horizontal position to be. again filled with the material to be excavated.

By the construction as thus described it will be seen that when'the excavator bucket has been hoisted to a certain height the sup porting pulley block will have been moved rearwardly a sufficient distance to cause dumping of the bucket; and it will be found advantageous to predetermine the height at which this dumping action shall occur. This is accomplished by adjusting the relative length of cables 24 and 25 thereby increasing or decreasing as required, the length of movement of the supporting pulley block relative to the excavator bucket. This adjustment of cables 24 and 25 may comprise the following construction:

An eye 26 is connected to the rear end of the excavator bucket as by cables 27 secured to I-bolts 28, and the eye 26 is provided with a recess 29 at one side thereof in which a link of cable 24 is adapted to be wedged for securingthe cable relative to the eye. By wedging any one of the links of the end of cable 24 in the eye 26 the length of said cable may be adjusted as desired.

Similar adjusting means are provided for cable 25 at the forward end of the excavator bucket, an eye 30 being connected to said end of the bucket as by cables 31 secured to I-bolts 32 and any one of the end links of the cable 25 being adapted to be wedged in a recess 33 provided in the eye 30.

Various changes may be made without dcparting from the spirit of the invention as claimed.

What is claimed is:

1. In a drag line excavator, an excavating bucket, and a supporting pulley for said bucket having a hoisting cable connected thereto, and arranged so that throughout the 7 rotation of said pulley, as the bucket is raised, said pulley will continually shift relative to said bucket to one side of the center of gravity thereof to ca use the bucket to tilt and dump when hoisted.

2. In a drag line excavator, an excavating bucket, a supporting pulley for said bucket having a hoisting cable connected thereto, and arranged so that throughout the rotation of said pulley, as the bucket is raised, said pulley will continually shift relative to said bucket to one side of the center of gravity thereof to cause the bucket to tilt and dump, and means for adjusting the height at which said pulley will have shifted sufiiciently to cause said bucket to tilt and dump.

3. In a drag line excavator, an excavating bucket, a supporting pulley, and a supporting cable attached to opposite ends of said bucket and engaged by said pulley in such manner that throughout the rotation of said pulley, as the pulley and bucket are raised, said pulley is continually shifted along said cable to one side of the center of gravity of the bucket to cause the latter to tilt and dump.

4. In a drag line excavator, an excavating bucket, a supporting pulley, and a. support ing cable'attached to opposite ends of said bucket and en aged by said pulley, said pulley arrangec to be rotated as the bucket and pulley are raised to continually shift said pulley along said cable to one side of the center of gravity of the bucket to cause the latter to tilt and dump.

5. In a drag line excavator, an excavating bucket, a supporting pulley, a hoisting cable engaging said pulley so as to rotate the same as the pulley and bucket are raised, and a supporting cable attached to opposite ends of said bucket and engaged by said pulley in such manner that as said pulley is rotated it is continually shifted along said cable to one side of the center of gravity of the bucket to cause the latter to tilt and dump.

6. In a drag line excavator, an excavating bucket, a supporting pulley, a supporting cable attached at its opposite ends to opposite ends of said bucket and engaged by said pulley intermediate of its ends in such numner that said pulley, as the pulley and bucket are raised, is continually s ifted along said cable to one side of the center of gravity of the bucket to cause the latter to tilt and dump, and means for adjusting the length of said cable between said pulley and bucket.

7. In a drag line excavator, an excavating bucket, a sup orting pulley, a sup orting cable for said ucket engaged by said pulley intermediate of its ends in such manner that said pulley, as the ulley and bucket are raised, is continual y shifted along said cable to one side of the center of gravity of the bucket to cause the latter to tilt and dump, connecting means at o posite ends of said bucket, and means for a justably securing the ends of said supporting cable to said connectin means for adjusting the length of said ca 1e between said pulley and bucket.

8. In a drag line excavator, an excavating bucket, a su porting pulley, a sup orting cable attached to opposite ends of em bucket and engaged by said pulley, and a hoisting cable engaging the pulley for raisin said pulley and bucket, said hoisting cab e arranged to rotate said ulley as it is raised to continually shift said pulley along said supportin cable to one side of the center of gravity 0 the bucket to cause the latter to tilt and dump.

9. In a drag line excavator, an excavating bucket, a supporting pulley, a supporting cable attached to op osite ends of said bucket and engaged b said pulley, hoisting pulleys at opposite sides of said supporting pulley, and a hoisting cable runnlng successively over said hoisting pulleys for raising the pulleys and bucket, said hoisting cable arranged to rotate the pulleys as they are raised to continually shift the supporting pulley along said supporting cable to one side of the center of gravity of the bucket to cause the latter to tilt and dump.

In testimony whereof I have signed my name to this s ecification.

LLIAM H. CRAWFORD. 

